a lot of them do it because you have an easy to use base, and they find it fun trying to fit a design to it. same reason there's so many OCs out there, it's an easy frame to work with. Just add a few features and you have yourself content!

if only it wasn't so terribly done all the time

^the guy who legitimately drew this spent several days trying to convince me on steam to tell him what tablet to buy so he could draw his OC better. He refused to take my advice of drawing first on paper and working on his skill (IE the ability to draw anything in the first place), as he hates the 'feel' of paper and "it would take too long". His budget was also $30 at most, so good luck

after me not cooperating for a good week, he eventually decided on his own that his nintendo 3DS was "close enough to a tablet computer" (I swear he called it a tablet oh man) and he started drawing on that. A week later he shut down his 'ask me' tumblr with the OC because he didn't get enough followers and his art wasn't improving good enough. he literally said "I spent days trying to get better but I still don't get any views!", deleting the blog thereafter

I don't know how he got in my steam list but it was too funny to delete him

There is no scientifical explenation, but one can assume they just do it to piss non-bronies the fuck off.

I think most people just wonder how X would look like in pony form and like the little artistic challenge of finding key features and applying them to the base.
The show itself did it with several references to other shows and franchises (like Doctor Who), that's pretty much an invitation to do that.

If something gets popular, the internet is simply permeated with fanart, OCs and crossovers.

a lot of them do it because you have an easy to use base, and they find it fun trying to fit a design to it. same reason there's so many OCs out there, it's an easy frame to work with. Just add a few features and you have yourself content!

if only it wasn't so terribly done all the time

^the guy who legitimately drew this spent several days trying to convince me on steam to tell him what tablet to buy so he could draw his OC better. He refused to take my advice of drawing first on paper and working on his skill (IE the ability to draw anything in the first place), as he hates the 'feel' of paper and "it would take too long". His budget was also $30 at most, so good luck

after me not cooperating for a good week, he eventually decided on his own that his nintendo 3DS was close enough to a tablet computer and he started drawing on that. A week later he shut down his 'ask me' tumblr with the OC because he didn't get enough followers and his art wasn't improving good enough. he literally said "I spent days trying to get better but I still don't get any views!"

I don't know how he got in my steam list but it was too funny to delete him

By doing a deep analysis on this strip in question, we can acquire enough knowledge to confirm that Preston doesn't have the required understanding of humorous comic strips in order to create humourful content, as it seems that the artist being analysed here thinks that one can create humour by "adding a joke" in a "jokeless strip", instead of developing the strips with humour in mind.

tl;dr Preston, you're doing it wrong, you should first think about the joke and then draw the strips with that in mind.